C From http://www.osc.edu/supercomputing/training/mpi/mpi_0504.pdf   
  INTEGER type1, type2 
  CALL MPI_TYPE_CONTIGUOUS(5, MPI_REAL, type1, ierr) 
! new type object created 
  CALL MPI_TYPE_COMMIT(type1, ierr) 
! now type1 can be used for communication 
  type2 = type1 
! type2 can be used for communication 
! (it is a handle to same object as type1) 
  CALL MPI_TYPE_VECTOR(3, 5, 4, MPI_REAL, type1, ierr) 
! new uncommitted type object created 
  CALL MPI_TYPE_COMMIT(type1, ierr) 
! now type1 can be used anew for communication
